WPF组合框阻止选择更新
WPF组合框阻止选择更新
提问于 2018-06-12 00:22:40
我有一个看起来像这样的ComboBox：
我不希望在选择其中一项时...的值发生变化。
我尝试过很多不同的解决方案--在SelectedIndex，SelectedValue，SelectionChanged上进行各种绑定，使用IsEditable，IsReadonly，IsHitTestVisible，让...成为一个实际的项目，让它成为占位符文本，等等等等。
每次我选择一个项目时，...都会使用子值更新。我希望它保持不变。
如何防止组合框在选择时自动更新文本，但仍然可以选择一个选项？
如果有帮助，下面是该图像的自定义模板：
<ResourceDictionary
x:Class="ComboBoxA"
xmlns:local="clr-namespace:MyTemplates"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ControlTemplate x:Key="ComboBoxA" TargetType="{x:Type ComboBox}">
<Grid>
<ToggleButton
ClickMode="Press"
Focusable="false"
IsChecked="{Binding Path=IsDropDownOpen,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}"
Name="ToggleButton"
>
<ToggleButton.Template>
<ControlTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="36" />
</Grid.ColumnDefinitions>
<Border
x:Name="Border"
Grid.ColumnSpan="2"
CornerRadius="0"
BorderThickness="1" />
<Border
Grid.Column="0"
CornerRadius="0"
Margin="1"
Background="Transparent"
BorderThickness="0"
/>
<Path
x:Name="Arrow"
Grid.Column="1"
Fill="#707070"
HorizontalAlignment="Center"
VerticalAlignment="Center"
Visibility="Collapsed"
Data="M0,0 L8,0 L4,4 z"
/>
<TextBlock
Margin="4,6"
Foreground="#282828"
Grid.Column="0"
Text="{Binding Path=(local:ComboBoxAHelper.Placeholder), RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}"
/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter TargetName="Arrow" Property="Visibility" Value="Visible"/>
<Setter TargetName="Border" Property="BorderBrush" Value="#d9d9d9"/>
</Trigger>
<Trigger Property="ToggleButton.IsChecked" Value="true">
<Setter TargetName="Arrow" Property="Visibility" Value="Visible"/>
<Setter TargetName="Border" Property="BorderBrush" Value="#d9d9d9"/>
</Trigger>
<DataTrigger Binding="{Binding Path=(local:ComboBoxAHelper.ShowBorders), RelativeSource={RelativeSource TemplatedParent}}" Value="True">
<Setter TargetName="Arrow" Property="Visibility" Value="Visible"/>
<Setter TargetName="Border" Property="BorderBrush" Value="#d9d9d9"/>
</DataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</ToggleButton.Template>
</ToggleButton>
<ContentPresenter
Content="{TemplateBinding SelectionBoxItem}"
ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"
HorizontalAlignment="Left"
IsHitTestVisible="False"
Margin="3,3,23,3"
Name="ContentSite"
VerticalAlignment="Center"
/>
<Popup
AllowsTransparency="True"
Focusable="False"
IsOpen="{TemplateBinding IsDropDownOpen}"
Name="Popup"
PopupAnimation="Slide"
>
<Grid Name="DropDown"
MaxHeight="{TemplateBinding MaxDropDownHeight}"
MinWidth="{TemplateBinding ActualWidth}"
SnapsToDevicePixels="True"
>
<Border
Background="White"
BorderBrush="#d9d9d9"
BorderThickness="1"
x:Name="DropDownBorder"
/>
<ScrollViewer Margin="4,6" SnapsToDevicePixels="True">
<StackPanel
IsItemsHost="True"
KeyboardNavigation.DirectionalNavigation="Contained"
/>
</ScrollViewer>
</Grid>
<Popup.Style>
<Style TargetType="Popup">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=(local:ComboBoxAHelper.RightAlignPopup), RelativeSource={RelativeSource TemplatedParent}}" Value="True">
<Setter Property="Placement" Value="Left" />
<Setter Property="VerticalOffset" Value="{Binding ActualHeight, RelativeSource={RelativeSource TemplatedParent}}" />
<Setter Property="HorizontalOffset" Value="{Binding ActualWidth, RelativeSource={RelativeSource TemplatedParent}}" />
</DataTrigger>
</Style.Triggers>
</Style>
</Popup.Style>
</Popup>
</Grid>
</ControlTemplate>
<Style x:Key="ComboBoxAItem" TargetType="{x:Type TextBlock}">
<Setter Property="FontSize" Value="12" />
<Setter Property="Foreground" Value="#282828" />
<Setter Property="Padding" Value="4" />
</Style>
</ResourceDictionary>...and它对应的XAML：
<ComboBox
templates:ComboBoxAHelper.Placeholder="..."
templates:ComboBoxAHelper.RightAlignPopup="True"
templates:ComboBoxAHelper.ShowBorders="True"
HorizontalAlignment="Right"
IsReadOnly="True"
IsEditable="False"
SelectedValue="x:Null"
Template="{StaticResource ComboBoxA}"
>
<ComboBoxItem>
<TextBlock Style="{StaticResource ComboBoxAItem}">Close</TextBlock>
</ComboBoxItem>
<ComboBoxItem>
<TextBlock Style="{StaticResource ComboBoxAItem}">Delete</TextBlock>
</ComboBoxItem>
</ComboBox>回答 1
Stack Overflow用户
回答已采纳
发布于 2018-06-12 04:32:04
诀窍就是移除
Content="{TemplateBinding SelectionBoxItem}"来自模板(包括一般代码和问题中发布的代码)。
感谢@Shadow32对我单独的问题https://stackoverflow.com/a/50805408/385273的回答。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/50802165
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